Hi @NurNida ,
Do you want the LookUp formula to be executed once time when you submit your form data?
Based on the needs that you mentioned, I think it is not necessary to display the LookUp result within the Category PIC Text Box, instead, you could configure Category PIC field as hidden field within your Edit form.
I agree with @WarrenBelz 's thought almost, you just need to bind the Update property of the Category PIC field data card to the LookUp result that you mentioned.
Set the Update property of Category PIC field data card in your Edit form to following:
If(
SharePointForm1.Mode = FormMode.New,
If(
IsBlank(DataCardValue12.Text) || DataCardValue12.Text = "Submitted",
LookUp('RFQ Request Category', Title = DataCardValue4.Selected.Value, CategoryPIC),
DataCardValue33.Text
),
Parent.Default
)
Best regards,